Abstract: A single channel video push effect generates push snapshots by combining a portion of a new video source with a complementary portion of an old video source to produce a combined image. Then the new and old video source portions of the combined image are swapped to produce a push snapshot. A sequence of such snapshots with increasing portions of the new video source forms the push effect.

Abstract: A low jitter direct digital frequency synthesized frequency shift keyed modulator has a tapped delay line to provide polyphase sampling of an asynchronous data input signal. The samples from the tapped delay line are input to a correction signal generator that produces a correction signal as a function of the location of data transitions in the data input signal with respect to a specified point of a sample clock pulse. The correction signal is used to offset a modulating input to a direct digital frequency synthesizer so that the frequency shift keyed output reflects the data transitions within 1/n of the period of the sample clock pulse.

Abstract: A digital decoder for an encoded video signal has three stages. The first stage applies a multi-dimensional digital chrominance bandpass filter to the digitized encoded video signal to produce a chrominance signal, subtracting the chrominance signal from the digitized encoded video signal to produce a luminance signal. The second stage detects edges and peaks in the chrominance signal, and corrects the luminance signal where such edges and peaks are detected to produce a chrominance corrected luminance signal without dot crawl errors. An intermediate corrected chrominance signal may also be derived from the second stage. The third stage filters the chrominance signal, or intermediate corrected chrominance signal, to reduce peaks in the chrominance signal as well as to enhance edges to produce a corrected chrominance signal with minimized cross color errors.

Abstract: A touch pad machine control system uses a touch pad having an overlay to define control strip surface areas which perform different functions. The contact of an operator's finger along one of the defined control strips selects a desired function and produces the desired machine motion from the rate, distance or duration of finger contact according to the desired function. The result is equivalent control motion without the need for moving parts.

Abstract: A non-linear keyer breaks a key processor transfer function into two pieces, one above and one below a clip level. Each piece may be modified independently and then recombined to produce the desired non-linear transfer function.

Abstract: An adaptive rounder for avoiding truncation errors for digital video signal has a dither source that is modified by the bits of an integer portion of an input digital signal corresponding to the video signal. A dither signal from the dither source has a number of bits equal to a fractional portion of the input digital signal. The dither signal is added to the input digital signal and the result is truncated to produce an output digital signal having a number of bits equal to the integer portion.

Abstract: Video effects apparatus comprises a wipe generator for generating a wipe signal and a matte generator for generating a matte signal. The matte generator receives the wipe signal and the color represented by the matte signal is dependent on the wipe signal. First and second control signals are provided in response to the wipe signal. A first video mixer has signal input terminals connected to receive a first video signal and the matte signal respectively and a mix control input terminal connected to receive the first control signal as a mix control signal, and a second video mixer has signal input terminals connected to receive respectively a second video signal and the output signal of the first video mixer. The second mixer has a mix control input terminal connected to receive the second control signal as a mix control signal.

Abstract: A digital memory delay line for a video border generator digitizes an insert video key signal and stores the digitized key signal in a digital memory. The locations in the memory are addressed sequentially in a continuous cycle so that as each location is addressed the portion of the key signal stored there is read out to reconstruct the key signal delayed by the cycle time, and a new portion of the key signal is written in. A clock for an address counter that provides addresses for access to the memory has a frequency that is a function of the number locations in the memory and the desired delay of the key signal. The delayed key signal from the memory is written back into the memory in parallel with the current key signal to provide a second output that is delayed by an additional address sequence cycle. The result is to reproduce the insert video key signal delayed for one horizontal line interval and for two horizontal line intervals.

Abstract: A recursive video blur effect is obtained by inserting a lowpass filter into a recursive feedback loop. Each pass of an output video signal through the recursive feedback loop successively smears the image represented by the video signal so that, when combined with an input video signal to produce the output video signal, a smoky fade effect is produced.

Abstract: A touchpad jogger for emulating operator contact with a touchpad surface has a ball rotatably mounted at the end of a spring arm cantilever mounted to one end of an axle. A knob is fixedly mounted to the other end of the axle so that when the knob is rotated the ball is caused to roll across the touchpad surface to emulate operator contact. A plate through which the axle extends provides for attaching the touchpad jogger to a housing containing the touchpad surface.

Abstract: A digital input signal having a sampling frequency f is interpolated by a factor N, where N is a positive integer, whereby a first digital signal having a sampling frequency Nf is generated. A non-linear operation is carried out on the first digital signal having the sampling frequency Nf and a second digital signal having the sampling frequency Nf is provided. The second digital signal is decimated by the factor N and thereby provides a digital output signal having the sampling frequency f.

Abstract: A mix effects based switcher architecture provides for processing of video signals with associated key signals throughout, the mix effects (M/E) banks within the switcher outputting both a composited video signal and a composited key signal for use by subsequent M/E banks. The outputs of the M/E banks may be combined together before being input to an output M/E bank. The output M/E bank provides a layered video signal with associated composited key signal at the output of the switcher.

Abstract: A rotary control knob is adapted to provide for automatic switching between two modes of movement control for a tape transport. An insulative ring surrounds a conductive knob, and the conductive knob is electrically connected to an oscillator circuit. Changes in the oscillator frequency due to operator contact with the conductive knob during movement of the knob are sensed to produce one mode of movement control, while movement of the knob due to operator contact with the insulative ring do not affect the oscillator frequency and indicate an alternative, default mode of movement control. A stepper motor is mechanically coupled to the control knob, and is electrically engaged in the default mode and disengaged in the one mode.

Abstract: An adaptive architecture for video effects allows a transformed image from a digital video effects (DVE) system to be inserted at any desired point along a video path through a production switcher while maintaining strict timing reqirements between the digital video effects system and the production switcher. The transformed image from the DVE system is input to a primary input bus as well as to a fill video input of a dowstream keyer (DSK) for the production switcher. A key signal from the DVE system is input to an effects key input and a key input of the DSK for the production switcher. The DVE system has a genlock timing system that provides a variable output timing signal to synchronize the transformed image with the video of the production system at the desired point of insertion along the video path.

Abstract: Shaping of automatic audio crossfade is accomplished by adding a shaping function to the theoretical logarithmic crossfade function to decrease the rate of gain change at the limit of audibility. The gain change at each sample time within a crossfade interval is computed as a logarithmic function of the fractional part of the crossfade interval completed and the gain differential between the sources. The shaping function may be in the form of a cosine function that can be accessed with a look-up table that is added to the fractional part of the crossfade interval so that the gain change is expressed by:ti G.sub.delta =20*log{(k-s(k))*10.sup.(G.sbsp.1.sup.-G.sbsp.2.sup.)/10 }where S(k) is the shaping function, k is the fractional part complete and G.sub.1 -G.sub.2 is the gain differential between sources. The gain change is added to the current gain for the particular audio source and applied to a variable gain element for that source.

Abstract: An improved luminance video self keyer extracts a key signal from an unshaped input video signal as a function of a low and a high clip level. The input video signal is subsequently "shaped" as a function of the key signal and the low clip level. The result is a shaped video signal and an associated key signal that are combined with a secondary video signal without resorting to double multiplication of the input video signal by its associated key signal to produce a desired combination of the two video signals.

Abstract: An improved self keyer preconditions a fill video prior to mixing with a background video under control of a self key signal derived from the fill video. A variable gray luminance signal is substituted for low luminance portions of the fill video under control of a precondition key signal derived from the self key signal to produce the preconditioned fill video. The resulting output video has a smooth luminance transition between the fill and background videos in lieu of an unpleasant black artifact at the edges of the fill video.

Abstract: A method for accumulating component video signals non-additively adds the luminance components to produce an accumulated luminance component, and additively adds the chrominance components to produce an accumulated chrominance component. The accumulated chrominance component may be clipped to limit chrominance values in an overlap area to legal color values. The intentional overlap of the component video signals produces an accumulation special effect in the overlap area.

Abstract: A transition interrupt for a video switcher which occurs at any point during or just prior to a transition between a program bus source and a preset bus source replaces the source on the preset bus with a new source. The program bus executes a cut or fade to black of the current source, and then the new source from the preset bus is switched to the program bus so that the new source is now on the program bus at black. The program bus is held at black, if necessary, until any necessary initial activation sequence is completed, such as preroll for a tape or cassette recorder, and then brought up from black to complete the new transition due to the transition interrupt.

Abstract: A frame format for a video codec combines video data at a video subcarrier frequency with up to five data channels at a DS1 digital telecommunications data rate and an optional audio/telephone channel. Video data is sampled and input to a stuff FIFO at the subcarrier frequency rate and output to a multiplexer at a DS3 digital telecommunications data rate. A stuff word is generated for each DS3 data subframe and contains either a valid data bit or a garbage data bit, as indicated by a stuff flag contained in the stuff word, to compensate for the difference in input and output data rates from the stuff FIFO. The DS3 master frame generated by a multiplexer from the video data and the other data channels is transmitted and decoded at the receiving end in a reverse manner.